Electronic devices, such as sonar transducers, have long been used in the fishing arts for determining water depth and locating fish. For example, sonar transducers are often mounted to a bottom portion of a trolling motor on a boat so that a fisherman may gather sonar information at a particular location to be fished. Unfortunately, such underwater electronics devices are notoriously fragile in both their construction and methods of attachment to a trolling motor. Very often, it is the sonar transducer that first contacts submerged vegetation, rocks, stumps, or other debris, and the like. Weeds and grasses also often ensnare on the sonar transducer, causing it to malfunction. Impact upon rocks, stumps, underwater debris, heavy grass/weed beds, or with stream, river, or lake beds usually results in damage to the sonar transducer. Replacing several transducers over the course of a busy fishing season can make fishing an unnecessarily costly pastime.
Various devices have been suggested in the art for guarding trolling motors and sonar transducers. For example, U.S. Pat. No. 4,902,255 discloses a weed guard for attachment to electric trolling motors having a motor housing and a motor support shaft. The weed guard includes a lower frame member portion and an upper arm portion. The triangular frame portion has a flange for attachment to the motor housing so that the frame portion has one apex toward the front of the motor housing and extends downwardly and rearwardly from the apex with respect to the motor housing at a constant angle. The upper arm portion is secured to the frame portion at the apex, and extends upwardly and forwardly. A rearward extension member extends from the upper arm portion toward the motor shaft for attachment to the motor shaft. This weed guard is not compatible with the use of a sonar transducer, since the triangular frame portion extends the entire length of the bottom of the motor, and would therefore block the sonar transducer from either sending or receiving signals, rendering the transducer useless.
In U.S. Pat. No. 6,421,301, provides a protective slip-on cover for a motor mounted sonar. The cover slips over and surrounds the transducer on at least three sides, leaving the bottom surface open for the transmission and reception of sonar signals. Thus, after installation of the shield, the transducer is free to operate in its usual manner with no effect upon its acquisition of sonar data. Although this design offers some level of protection, it may not completely deflect impact forces, particularly shearing forces from impact of the transducer upon a rock or stump. It also does not appear to provide against hang-up on weeds and grasses.
None of the foregoing devices have proved to be wholly effective in protecting sonar transducers during normal use. As a consequence, there has been a long felt need for a sonar transducer guard with improved protection from damage resulting from underwater impacts with hard objects, such as stream and lake beds, debris, and the like, as well as protection from hang-up upon weeds and grasses.